In contemporary optical-electronic hybrid systems, an optical fiber typically interfaces with an opto-electronic device. The opto-electronic device usually includes a hermetic package, having conductive leads for electronic communication with devices external to the package.
During manufacture, single or multiple fiber optic pigtails are inserted through ferrules provided in sidewalls of the package. Typically, pigtail-level assembly is usually performed manually by assembly personnel who visually align, and then insert, each fiber into its ferrule. The endface of each pigtail is typically positioned and secured to a bench or submount, which is installed within the package. The pigtail is also bonded to its corresponding ferrule to enable hermetic sealing of the package.
Additionally, it is also sometimes important to optimize the angular orientation of the fiber endface relative to the optical circuit in order to increase coupling efficiency and/or polarization extinction. Conventionally, angular control is achieved via manual rotation of the fiber prior to bonding by assembly personnel.
The present invention is directed to a system and method for automated fiber insertion into an opto-electronic hybrid package that overcome the limitations of conventional insertion techniques. In particular, the present invention provides for automated location and insertion of a pigtail into the ferrule, a possibly active or passive alignment to opto-electronic components within the package.
In general, according to one aspect, the invention provides for the mounting of a fiber on a fiber chuck, after which it is presented to the package by a system providing for four degrees of freedom. The degrees of freedom include the three orthogonal cardinal axes (x, y, and z-axes), and a fourth degree of freedom corresponding to angular rotation xcex8 about the z-axis. In this manner, the fiber is positioned in the ferrule of the package.
In some embodiments, feedback mechanisms are provided for the orthogonal (x, y, and z-axis) and angular positioning in order to optimize coupling efficiency and/or polarization extinction, for example, between the fiber and the electronic circuit mounted in the package.
In one implementation, the fiber chuck includes a longitudinal groove for seating the fiber during an alignment procedure. The groove interfaces preferably with a vacuum manifold that serves to seat the fiber in the chuck during alignment.
In the present implementation, the system includes a package mount for securing a package having an optical alignment feature.
The positioner may receive position data related to the position of the optical alignment feature, and may further utilize the position data during an alignment procedure.
In one embodiment, the positioner comprise a longitudinal bench, a lateral bench and a vertical bench, each bench being independently positionable along the directions of the respective longitudinal, lateral, and vertical axes. Position encoders are included for providing position data of the respective benches along the respective axes.
A fiber rotation drive is included for rotationally orienting the fiber about the longitudinal axis. In this case, an angular encoder provide angular data of the fiber about the longitudinal axis. A sensor may also be included in the package mount for receiving optical signals transmitted along the fiber optic during an alignment operation, and for providing intensity data to the positioner.